Antibacterial function of herbal extracts on growth, survival and immunoprotection in the black tiger shrimp Penaeus monodon

An Overview of the Biological Functions and Mechanisms of Action of Medicinal Plants and Seaweeds in the Shrimp Culture

Diseases are major constraints to developing large-scale aquaculture practices in many countries. For decades, synthetic chemotherapeutic agents have been widely applied both as prophylactics and therapeutics to inhibit and control aquatic disease outbreaks. However, their use has become more restricted due to the negative impacts they have on the environment, the host and humans, as well as their limitations in preventing the emergence of antimicrobial-resistant bacteria. Therefore, there is a growing interest in the use of medicinal plants and seaweeds as potential alternatives to antibiotics and other synthetic chemotherapeutics. Medicinal plants and seaweeds can enhance the immune systems of animals, thereby providing protection against numerous diseases while minimizing the adverse effects associated with synthetic chemotherapeutics. Furthermore, the advantages of medicinal plants and seaweeds, such as their effectiveness, easy availability and ability to be applied on a large scale, make them appealing for use in the aquaculture industry. The main goal of this study was to review the existing knowledge of the effects of medicinal plants and seaweeds, as well as their extracts, on shrimp growth, immune response and disease resistance against bacterial and viral agents. Moreover, this paper discusses the application of seaweeds in shrimp culture. We also conducted a literature review to identify gaps in the research and provide recommendations for further advancement in this field of study. Further studies should focus on evaluating other physiological aspects, such as feed and mineral utilization, enzyme activities and histological examination.

Effects of a phytobiotic-based additive on the growth, hepatopancreas health, intestinal microbiota, and Vibrio parahaemolyticus resistance of Pacific white shrimp, Litopenaeus vannamei

Vibrio genus is a common pathogen in aquaculture and causes acute hepatopancreatic necrosis disease (AHPND) and massive mortality of shrimp. Many studies have suggested that a single functional ingredient such as plant extract or organic acid can reduce the dependence on antibiotics and promote the growth and immunity of aquatic animals. In this study, we evaluated the effects of a phytobiotic-based compound additive (Sanacore® GM, SNGM), which had a successful trajectory of commercial application in fish farming. However, its effects on the hepatopancreas health and intestinal microbiota of shrimp after Vibrio challenge have not been well evaluated. In the present study, Pacific white shrimp were fed diets with or without supplementation of SNGM, and the SNGM grades were 0-g/kg (CON), 3-g/kg (SNGM3), and 5-g/kg (SNGM5) diets. The feed trial lasted 60 days, after which a Vibrio parahaemolyticus challenge was performed. The results showed that compared to the CON group, both the SNGM3 and SNGM5 groups had a significantly higher weight gain and a lower feed conversion ratio as well as higher survival after Vibrio parahaemolyticus challenge. In the growth trial, the SNGM3 group had a significantly increased total protein, albumin concentration, and acid phosphatase activity in hemolymph compared to the CON group. In the challenge experiment, the SNGM3 and SNGM5 groups had increased albumin and glucose contents as well as the activities of phenoloxidase, lysozyme, alkaline phosphatase, and superoxide dismutase in hemolymph. Both the SNGM3 and SNGM5 groups had improved morphology of the hepatopancreas and intestine. The SNGM5 group had alleviated gut microbiota dysbiosis induced by Vibrio infection by increasing the potential probiotic bacterium abundance (Shewanella) and decreasing the potential pathogenic bacteria abundance (Vibrio, Photobacteriuma, Pseudoalteromonas, and Candidatus_Bacilloplasma). In conclusion, the dietary phytobiotic-based additive at 3-g/kg level increased the growth and Vibrio parahaemolyticus resistance of Pacific white shrimp by promoting immune-related enzyme activities and improving the morphological structure of the hepatopancreas and intestine and the intestinal microbiota composition.

Exploring beneficial effects of phytobiotics in marine shrimp farming: A review

Marine shrimp farming, mainly Penaeus monodon and Litopenaeus vannamei, is an important component of the aquaculture industry. Marine shrimp farming helps produce a protein source for humans, provides job opportunities, and generates lucrative profits for investors. Intensification farming practices can lead to poor water quality, stress, and malnutrition among the farmed marine shrimp, resulting in disease outbreaks and poor production, impeding the development of marine shrimp farming. Antibiotics are the common short-term solution to treat diseases in marine shrimp farming. Moreover, the negative impacts of using antibiotics on public health and the environment erode consumer confidence in aquaculture products. Recently, research on using phytobiotics as a prophylactic agent in aquaculture has become a hot topic. Various phytobiotics have been explored to reveal their beneficial effects on aquaculture species. In this review paper, the sources and modes of action of phytobiotics are presented. The roles of phytobiotics in improving growth performance, increasing antioxidant capacity, enhancing the immune system, stimulating disease resistance, and mitigating stress due to abiotic factors in marine shrimp culture are recapitulated and discussed.

Harnessing probiotics and prebiotics as eco-friendly solution for cleaner shrimp aquaculture production: A state of the art scientific consensus

In recent years, the advancement and greater magnitude of products, which led to the intensification in shrimp aquaculture is the result of utilization of modern tools and synchronization with other fields of science like microbiology and biotechnology. This intensification led to the elevation of disorders such as the development of several diseases and complications associated with biofouling. The use of antibiotics in aquaculture is discouraged due to their certain hazardous paraphernalia. Consequently, there has been a growing interest in exploring alternative strategies, with probiotics and prebiotics emerging as environmentally friendly substitutes for antibiotic treatments in shrimp aquaculture. This review highlighted the results of probiotics and prebiotics administration in the improvement of water quality, enhancement of growth and survival rates, stress resistance, health status and disease resistance, modulation of enteric microbiota and immunomodulation of different shrimp species. Additionally, the study sheds light on the comprehensive role of prebiotics and probiotics in elucidating the mechanistic framework, contributing to a deeper understanding of shrimp physiology and immunology. Besides their role in growth and development of shrimp aquaculture, the eco-friendly behavior of prebiotics and probiotics have made them ideal to control pollution in aquaculture systems. This comprehensive exploration of prebiotics and probiotics aims to address gaps in our understanding, including the economic aspects of shrimp aquaculture in terms of benefit-cost ratio, and areas worthy of further investigation by drawing insights from previous studies on different shrimp species. Ultimately, this commentary seeks to contribute to the evolving body of knowledge surrounding prebiotics and probiotics, offering valuable perspectives that extend beyond the ecological dimensions of shrimp aquaculture.

Andrographis paniculata improves growth and non-specific immunity of shrimp Litopenaeus vannamei, and protects it from Vibrio alginolyticus by reducing oxidative stress and apoptosis

Andrographis paniculata (AP) is a traditional medicinal plant with many pharmacological activities, including anti-inflammatory, antimicrobial, immunity stimulation and so on. Several studies have reported that AP plays a strong role in promoting the immune system of aquatic animals to resist several pathogens. In the present study, we investigate the effects of a diet containing AP on the immune responses, growth, and the resistance to Vibrio alginolyticus (V. alginolyticus) in Litopenaeus vannamei (L. vannamei). Four diets were formulated by adding AP at the dosage of 0% (Control), 0.25%, 0.5%, and 1% in the basal diet, respectively. Each diet was randomly fed to one group with three replicates of shrimps in a 28-day feeding trial. The results showed that dietary AP improved the growth performance and non-specific immune function of shrimps. To investigate the effect of AP on disease resistance of L. vannamei, shrimps fed with diet containing AP were challenged with V. alginolyticus. Compared with the control group, the shrimps fed diet containing AP showed significantly higher survival. Furthermore, the hepatopancreas injury in the shrimp fed with AP was less than control group at 6 h after V. alginolyticus infection. However, no difference was observed in the degree of hepatopancreas injury between AP groups and control group at 12 h and 24 h after V. alginolyticus infection. Based on this result, the samples at 6 h after V. alginolyticus infection was selected for subsequent detection. Reactive oxygen species (ROS) accumulation in hemocytes and O₂^- production in hepatopancreas caused by V. alginolyticus infection was significantly reduced after feeding a diet containing 0.25% and 0.5% AP (p < 0.05). In addition, we found that feeding AP significantly up-regulated the expression of pro-apoptotic genes (Bax, Caspase 3, p53) and down-regulated the expression of anti-apoptotic genes (Bcl-2) in hepatopancreas after V. alginolyticus infection. In conclusion, AP promote the growth and immunity of L. vannamei, and protects shrimps against V. alginolyticus by regulating the oxidative damage and apoptosis. These results provide useful information regarding the effects of AP extracts as a shrimp feed additive for sustainable shrimp culture.

Application of Phyto-Stimulants for Growth, Survival Rate, and Meat Quality Improvement of Tiger Shrimp (Penaeus monodon) Maintained in a Traditional Pond

The tiger shrimp culture in East Borneo is commonly performed using traditional pond system management. In this work, the objective was to evaluate the application of Boesenbergia pandurata and Solanum ferox extract supplemented as feed additives considering shrimp growth, survival rate, and meat quality culture in a traditional pond. There were three dietary groups that were stocked with 300 shrimp in this study. The shrimp were maintained in a pond, separated with a 3 × 3 m² net. The dietary treatment applied was divided into three types, namely P1, without the extracts; P2, 20 mL kg⁻¹ dietary supplementation; and P3, 30 mL kg⁻¹ dietary supplementation in the diet. The findings revealed that the herb extract influenced the growth rate, feed efficiency, survival rate, and meat quality of the shrimp, mainly the amino and fatty acid contents in the shrimp meat. The 30 mL kg⁻¹ herb extract dose in group 3 showed a higher growth performance and survival rate. In group 3, 98% of the shrimp could survive until the final study period, while 96% of shrimp survived in group 2, and 70% of the shrimp survived in group 1. These findings indicate that the phytoimmune (B. pandurata and S. ferox) extract can be utilized as a feed additive to improve the growth, survival rate, and meat quality of the shrimp.

Pharmacological and ameliorative effects of Withania somnifera against cadmium chloride-induced oxidative stress and immune suppression in Nile tilapia, Oreochromis niloticus

This study was carried out to evaluate the effects of dietary supplementation of aqueous extract of Withania somnifera (W. somnifera) against cadmium chloride-induced toxicity in the Nile tilapia, Oreochromis niloticus. Five experimental groups were designed: group (I) was free from cadmium chloride and W. somnifera and served as a control, group (II) was exposed to 1.775 mg L^-1 of cadmium chloride only (which is equivalent to 1/4 96-h LC50), while groups (III), (IV), and (V) were exposed to 1.775 mg cadmium chloride L^-1 with co-supplementation of dietary W. somnifera in doses of 1.0, 2.0, and 3.0 mL kg^-1 body weight (bwt), respectively. The experiment lasted for 4 weeks. In the second and fourth weeks of the experiment, the following indicators were evaluated: hematological (hemogram and blood protein profile), biochemical (activities of serum liver enzymes, namely alanine transaminase (ALT) and aspartate transaminase (AST)), immunological (immunoglobulin M (IgM), serum lysozyme), and tissue antioxidant changes (malondialdehyde (MDA) levels and activities of catalase (CAT) and superoxide dismutase (SOD)). Additionally, gene expressions of glutathione-S-transferase (GST) in the liver were assessed. At the end of the experiment, all fish in all groups were experimentally challenged with Aeromonas hydrophila and the relative protection survival (RPS) was demonstrated. The results revealed that groups exposed to cadmium chloride toxicity and co-supplemented with dietary aqueous extract of W. somnifera at high doses showed significant ameliorative effects in hemogram parameters, total protein, globulin, IgM, and lysozyme against cadmium chloride-induced toxicity compared to the control group and the group exposed to a sublethal dose of cadmium chloride without co-suplemntation of W. somnifera. The results showed also that groups supplemented orally with W. somnifera at high doses have higher antioxidant activities of CAT and SOD and reduction of MDA formation. Levels of gene expressions of GST in the liver were higher in W. somnifera extract-supplemented groups more than those in the group exposed to cadmium chloride-induced toxicity without W. somnifera supplementation. In addition, the results revealed improved RPS with the dietary supply of W. somnifera extract in high doses. In conclusion, this study showed that the dietary supplementation of W. somnifera extract to diets of O. niloticus could be suggested as an effective way to overcome cadmium chloride-induced toxicity because it improves blood parameters and antioxidants, and it can be used as an immunostimulant against the invading bacterial pathogens.

Effect of dietary supplementation of Neem, Azadirachta indica leaf extracts on enhancing the growth performance, chemical composition and survival of Rainbow trout, Oncorhynchus mykiss

Rainbow trout Oncorhynchus mykiss has a great nutritional value and delicious taste. A 90-days experimental trial was conducted to investigate the effect of dietary leaf extract of neem tree Azadirachta indica as a feeding supplement on the growth performance and proximate composition of O. mykiss. Four experimental diets were designed as T₁ (with 5% A. indica leaf extract), T₂ (with 7% of A. indica leaf extract), T₃ (with 10% A. indica leaf extract), and T₄ (control group feed with a regular diet with 0% A. indica leaf extract). The average initial weight of fry 0.4 ± 0.14 g was stocked at 25 fish/tank with two replicates per treatment (4 × 2 = 8). After 90 days of the experimental trial, One-way ANOVA showed significant differences in final body weight, weight gain, specific growth rate, feed conversion ratio, and survival rate among the treatment groups (p < 0.05). The highest final body weight (48.10 g) and weight gain (47.70 g) was observed in T2 with 7% A. indica leaf extract, which was significantly different from the other treatments (p < 0.05). The lowest FCR was recorded in T2 (1.90), which was significantly different compared to other treatment groups (p < 0.05). Inclusion of A. indica leaf extract in formulated feed for rainbow trout had significant effects in the hepatosomatic index, viscerosomatic index and Fulton’s condition factor (p < 0.05), but there was no significant difference in the survival rate of rainbow trout fry treated with different experimental diets (p > 0.05). The phenomenal regression indicates that 7.5% A. indica inclusion is optimum for best growth performance for rainbow trout under a controlled environment. Thus, the present study suggests that the dietary leaf extract has performed an excellent nutritional supplement by enhancing growth performance and health conditions of rainbow trout in the hatchery conditions.

Moringa oleifera Leaves' Extract Enhances Nonspecific Immune Responses, Resistance against Vibrio alginolyticus, and Growth in Whiteleg Shrimp (Penaeus vannamei)

Simple Summary

This study found that moringa (Moringa oleifera) leaves’ water extract triggered phenoloxidase activity, phagocytic rate, and superoxide anion production in whiteleg shrimp (Penaeus vannamei) hemocytes by an in vitro assay. By an in vivo assay, a dietary moringa extract enhanced the total hemocyte count, phenoloxidase activity, phagocytic rate, immune-related gene expressions, and growth performance of the whiteleg shrimp. The administration of dietary moringa extract increased the survival rate after challenging the whiteleg shrimp with Vibrio alginolyticus.

Abstract

Moringa is widely known as a plant with high medicinal properties. Therefore, moringa has a high potential for use as an immunostimulant in shrimp. This study investigated the effect of a moringa water extract on the immune response, resistance against V. alginolyticus, and growth performance of whiteleg shrimp. To perform the in vitro assay, hemocytes were incubated with different concentrations of the moringa extract. Furthermore, the moringa extract was incorporated at 0 (control), 1.25 g (ME1.25), 2.5 g (ME2.5), and 5.0 g (ME5.0) per kg of diet for the in vivo assay. During the rearing period, immune responses, namely the total hemocyte count (THC), phenoloxidase (PO) activity, phagocytosis activity, superoxide anion production, and immune-related gene expression were examined on days 0, 1, 2, 4, 7, 14, 21, and 28. Growth performance was measured 60 days after the feeding period. Furthermore, the shrimp were challenged with V. alginolyticus after being fed for different feeding durations. The results of the in vitro assay revealed that 100–250 ppm of the moringa extract enhanced the PO activity, phagocytic rate (PR), and superoxide anion production. The findings of the in vivo assay demonstrated that the THC, PO activity, PR, and immune-related gene expression, including alpha-2-macroglobulin, prophenoloxidase II, penaeidin2, penaeidin3, anti-lipopolysaccharide factor, crustin, lysozyme, superoxide dismutase, and clotting protein, were higher in the group of ME.25 and ME5.0 than in the control and ME1.25 at several time points. Growth performance was significantly increased (p < 0.05) in the ME2.5 group compared to the control group. Furthermore, the dietary ME2.5 resulted in a higher survival rate compared to that of the control group after challenging with V. alginolyticus, especially at ME2.5 administered for 4 and 7 days. This study indicated that the incorporation of the moringa extract at 2.5 g per kg of diet enhanced the immune response, the growth performance of the whiteleg shrimp, and the resistance against V. alginolyticus infection.

Increasing disease burden and use of drugs and chemicals in Bangladesh shrimp aquaculture: A potential menace to human health

Using structured surveys in 2008 and 2016, change in disease burden and use of chemical treatments in Bangladesh shrimp farm management was examined. Overall, disease burden had increased in all farms and was more polarized, with a fewer number of individual infectious diseases responsible for most disease in ponds. Farmers also reported physical deformities, nutritional deficiencies, and unknown diseases further indicating poor health of their stock. To combat the threat, more chemical treatments were used (5.2 treatments per farm in 2008 versus 28.8 in 2016), resulting in an average increase of 424% in the number of active substances entering shrimp ponds. Although there was a modest reduction in the use of antimicrobials, shrimp was being exposed to a wider range of chemicals during rearing. The subsequent concern for the environment, animal and human health demands further research to identify potential risks from residues of chemical products.

Anti-vibrio and immune-enhancing activity of medicinal plants in shrimp: A comprehensive review

Disease epidemics in shrimp aquaculture increase apace with the development of aquaculture systems throughout the world. The disease caused by Vibrio spp. (vibriosis) is considered the most devastating, which has made it the most feared bacterial disease in the shrimp sector. In aquaculture, several strategies have already been applied to control Vibrio strains, including chemicals, probiotics, antibiotics, natural products from plants, including plant oils; hence, there has been considerable attention for using plants in shrimp aquaculture to provide sustainable, eco-friendly and safe compounds, such as alkaloids, saponins, terpenoids and flavonoids for replacing chemical compounds and antibiotics in current aquaculture. Medicinal plants may also have immunostimulating activity, increase growth and resistance in shrimps. The present paper aims to review the inhibition of Vibrio spp. in shrimp by medicinal plants, using both in vitro or/and in vivo techniques. Several medicinal plants appear capable of inhibiting growth of Vibrio pathogens outside living shrimp or in the body of shrimp, through enhancing growth and immune capacity when shrimps are fed or injected with them. In the current review Gracilaria spp. (Gracilariaceae family) and Sargassum spp. (family Sargassaceae) have been used most for in vitro and in vivo experiments. Among the terrestrial plants, Eucalyptus camaldulensis, Psidium guajava, Rhodomyrtus tomentosa, and Syzygium cumini (Myrtaceae family) had significant activity against Vibrio.

Effect of mangrove leaf extract (Acanthus ilicifolius) on non-specific immune status and vibriosis resistance of black tiger shrimps (Penaeus monodon) challenged with Vibrio harveyi

Background and Aim

There has been continuous effort to search for alternative medicinal plants that are applicable to ameliorate viral disease on shrimp pond. This study aimed to examine the effect of Acanthus ilicifolius leaf extract on clinical symptoms and non-specific immune response of black tiger shrimp (Penaeus monodon).

Materials and Methods

A total of 330 shrimps were equally assigned into three extract forms (crude extract, ethyl acetate extract, and n-butanol extract, respectively) in which three levels were provided for each extract. Negative control (without leaf extract) and positive control (with oxytetracycline at 0.05 mg/mL) were used, giving a total of 11 experimental treatments.

Results

The results showed that shrimps induced into all form of leaf extracts had significantly higher survival rates, clinical symptoms, and pathological anatomy than those negative control (C-) and positive control (C+). Total hemocyte cells, granulocytes, percentage of phagocytic, and prophenoloxidase activity were similar among leaf extract treatments (p>0.05), but those groups were significantly higher than those of C- and C+ (p<0.05).

Conclusion

n-butanol leaf extract at 300 mg/L is suggested to be the most effective treatment since it showed the highest efficacy on the parameters observed. Thus, it is possible to use the leaf extract of A. ilicifolius on-farm as a strategy to enhance bacterial disease resistance and prevent mortality.

Effects of Phyllanthus amarus extract on nonspecific immune responses, growth, and resistance to Vibrio alginolyticus in white shrimp Litopenaeus vannamei

This study investigates the effects of Phyllanthus amarus extract (PAE) on immune responses, growth, and resistance to Vibrio alginolyticus in white shrimp (Litopenaeus vannamei). In vitro PAE treatment did not alter the cell viability of haemocytes and significantly enhanced immune parameters such as phenoloxidase (PO) activity, phagocytic activity, and superoxide anion (O₂^-) production. We conducted two feeding trials to examine the effects of PAE on the growth, disease resistance, and innate immune parameters of white shrimp. In the first in vivo trial, shrimps (4.01 ± 0.03 g) were fed a diet containing 0 g (control), 10 g (PAE10), 20 g (PAE20), or 40 g (PAE40) of PAE per kilogram of feed for 56 days. After the feeding period, the PAE20 group showed a significantly higher weight gain and specific growth rate than shrimp fed the control diet. Furthermore, after challenge with V. alginolyticus, shrimp fed a diet containing PAE showed significantly higher survival than those fed the control diet. The second in vivo trial (28 days) was performed to identify the mechanisms of enhanced immunity in PAE-fed shrimp. Shrimp fed the PAE20 diet generally had the highest total haemocyte count, PO activity, phagocytic activity, and O₂^- production, followed by the PAE40 and PAE10 groups. Thus, our results suggest that administration of 20 g of PAE per kilogram of feed can enhance immunity, growth, and resistance to V. alginolyticus in white shrimp.

Effects of Dietary Andrographolide Levels on Growth Performance, Antioxidant Capacity, Intestinal Immune Function and Microbioma of Rice Field Eel (Monopterus Albus)

An eight-week feeding trial was conducted to investigate the effects of dietary andrographolide on the growth performance, antioxidant capacity in the liver, intestinal inflammatory response and microbiota of Monopterus albus. A total of 900 health fish (25.00 ± 0.15 g) were randomly divided into five groups: AD1 (the basal diet) as the control, and AD2, AD3, AD4 and AD5 groups, which were fed the basal diet supplemented with 75, 150, 225 and 300 mg/kg andrographolide, respectively. The results showed that compared with the control group, dietary andrographolide supplementation (1) significantly increased trypsin and lipase activities in the intestine, and increased the weight gain rate but not significantly; (2) significantly increased the levels of glutathione reductase (GR), glutathione (GSH) and glutathione peroxidase (GPx) and the content of in the liver; significantly decreased the contents of reactive oxygen species (ROS) and malondialdehyde (MDA); remarkably upregulated the Nrf2, SOD1, GSTK and GSTO mRNA levels in the liver; downregulated the Keap1 mRNA level; (3) significantly increased the villi length and goblet cell numbers in the intestine, remarkably upregulated the Occludin mRNA level in the intestine, downregulated the Claudin-15 mRNA level; (4) remarkably upregulated the IL-10, TGF-β1 and TGF-β3 mRNA levels in the intestine; downregulated the IL-12β and TLR-3 mRNA levels; (5) significantly decreased the richness and diversity of the intestinal microbioma, increased the percentages of Fusobacteria and Firmicutes and significantly decreased the percentages of Cyanobacteria and Proteobacteria. In conclusion, these results showed that dietary low-dose andrographolide (75 and 150 mg/kg) promoted growth and antioxidant capacity, regulated the intestinal microbioma, enhanced intestinal physical and immune barrier function in rice field eel.

Effects of Lactococcus lactis from Cyprinus carpio L. as probiotics on growth performance, innate immune response and disease resistance against Aeromonas hydrophila

In the present study, we reported 18 LAB strains isolated from the intestinal contents of Cyprinus carpio, and their probiotic properties both in vitro and in vivo. The results showed that 9 of them had higher in vitro immunomodulatory properties, effectively survived under acidic (pH 2.5) and bile salt (ranging from 0.1% to 0.5%) conditions, and inhibited the growth of 4 pathogens. Among them, Lactococcus lactis Q-8, Lactococcus lactis Q-9, and Lactococcus lactis Z-2 showed the strongest adhesion abilities and inhibition of pathogen adhesion to mucin. When the fish consumed diets containing these 3 strains (5 × 10⁸ CFU/g) for 8 weeks, the weight gain (WG) and specific growth rate (SGR) had significantly (P < 0.05) increased, especially with L. lactis Q-8, which had a WG of 231.45%, and SGR of 2.22%. Survival rate in each LAB supplementation group was also significantly higher than that in control group during the feeding period (P < 0.05). For the cytokines expression levels in serum, different expression patterns were also observed. Before the infection with Aeromonas hydrophila, L. lactis supplementation significant up-regulated protein levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-12) compared with negative (CK1) group, while these cytokines were significantly lower than those in positive (CK2) group after infection. However, whether infected or not, the expression of anti-inflammatory cytokines (IL-10, TGF-β) were significantly increased in L. lactis Q-8, L. lactis Q-9, and L. lactis Z-2 treatment groups. In conclusion, these 3 L. lactis strains screened from common carp were effective in improving growth, innate immunity and disease resistance. Based on the physiological characteristics in our study, they might be used as potential probiotics in aquaculture.

Response of hemocytes profile in the black tiger shrimp (Penaeus monodon) against Vibrio harveyi induced by Xylocarpus granatum leaves extract

Aim:

The present study investigated hemocytes profile of black tiger shrimp (Penaeus monodon) induced with Xylocarpus granatum leaves extract to protect against Vibrio harveyi infection.

Materials and Methods:

X. granatum leaves were chopped into small size, air-dried, and extracted with one of the following solvents: Ethanol, distilled water, and seawater, whereas each solvent was given in three different concentrations (750 ppm, 1.000 ppm, and 1.250 ppm, respectively). Extracts were induced to 60 post-larvae shrimp in each treatment (three replicates, 20 shrimp for each) by immersing method and subsequently challenged with V. harveyi.

Results:

This study demonstrated different effectiveness among solvents used to extract X. granatum leaves, in which distilled water showed the most effective solvent as can be seen from the lowest percentage on anorexia, lethargic, and weakened reflex of shrimp compared with another solvent, positive and negative controls. Pathological symptoms for shrimp induced by X. granatum leaves extract were minimum with the highest survival rate compared with those of positive and negative control. Total hemocyte cells and its cell constituents such as semi-granular, granular, and hyaline cells on treatment group at 1.250 ppm were higher than controls.

Conclusion:

Leaves extract of X. granatum extract effectively inhibited V. harveyi infection, increased survival rate, and hemocytes cell of the experimental shrimp. Distilled water extract of X. granatum at 1.250 ppm demonstrated the highest protective effect toward V. harveyi infection on P. monodon.

Modulation of growth performance and nonspecific immunity of red swamp crayfish Procambarus clarkia upon dietary fulvic acid supplementation

An eight-week experiment was conducted to determine the effects of dietary fulvic acids (FAs) on the growth performance, digestive enzymes and nonspecific immunity of red swamp crayfish Procambarus clarkia. Three diets supplemented with three different levels of FAs (0.1, 0.5 and 1 g kg^-1) were formulated and tested for the growth performance, digestive enzymes and nonspecific immunity of the crayfish, and a diet without FAs served as control. After eight weeks of feeding, survival rate, phenoloxidase activity, superoxide dismutase activity, glutathione peroxidase level, total haemocyte count and number of hyaline cells, semigranular cells and granular cells and resistance to Aeromonas hydrophila of crayfishes fed with FA-containing diets were higher than those of the control. Moreover, based on the efficiency of FAs on the growth performance and nonspecific immunity of crayfish, the optimum dose of FAs was found to be 0.5 g (kg diet)^-1. A high level of FA administration (1 g kg^-1) did not further increase the efficiency of FAs compared with those in the moderate group (0.5 g kg^-1, p > 0.05). Results indicated that oral administration of FA-containing diets can enhance the growth performance, intestinal digestive enzymes, immune responses and resistance of crayfish to infection by A. hydrophila. Thus, FAs may be utilized as a diet supplement for crayfish.

Effects of dietary trehalose on the growth performance and nonspecific immunity of white shrimps (Litopenaeus vannamei)

This study aimed to investigate the effects of trehalose on the growth performance and nonspecific immunity of white shrimps (Litopenaeus vannamei). The shrimps were randomly divided into four groups, i.e. control group fed with normal commercial diet and three treatment groups fed with trehalose-containing diets (0.5, 1 and 1.5 g kg^-1) and experimental diets during a 12-week breeding experiment. Oral trehalose administration significantly improved the body weight; food efficiency; survival rate; phenoloxidase activity; superoxide dismutase activity; glutathione peroxidase level; total haemocyte count; hyaline, semigranular and granular cell numbers; and disease resistance against Vibrio alginolyticus relative to those of the control group (p < 0.05). However, a high level (1.5 g kg^-1) of trehalose supplement did not further increase the efficiency compared with the moderate dose (1 g kg^-1). Results indicated that trehalose exerted immunostimulatory effects on Pacific white shrimps (L. vannamei) and may be used as a diet supplement for the crustaceans.

Stimulating effects of polysaccharide from Angelica sinensis on the nonspecific immunity of white shrimps (Litopenaeus vannamei)

Angelica sinensis polysaccharide (ASP) was prepared by hot water extraction. Then, high-performance liquid chromatography and ion chromatography analyses were conducted, and the results indicated that ASP is a heteropolysaccharide, has a molecular mass of 82,000 Da and consists of arabinose, galactose and glucose (molar ratio of 6:1:1). The effects of ASP on the nonspecific immunity of white shrimps (Litopenaeus vannamei) were investigated by feeding them with ASP-containing diets (0.5, 1 and 1.5 g/kg) during a 12-week breeding experiment. Oral ASP administration significantly improved the survival rate, phenoloxidase activity, superoxide dismutase activity, glutathione peroxidase level, disease resistance against V. alginolyticus, total haemocyte count and number of hyaline cells, semigranular cells and granular cells (p < .05). ASP exhibits immunostimulatory effects on Pacific white shrimps (L. vannamei) and may thus be used as a diet supplement for them.